GB2448691A

GB2448691A - Tilt Angle Sensor for Stability Control of a Vehicle.

Info

Publication number: GB2448691A
Application number: GB0707817A
Authority: GB
Inventors: Colin Ross; Matthew Fry
Original assignee: Knorr Bremse Systeme fuer Schienenfahrzeuge GmbH; Knorr Bremse Systems for Commercial Vehicles Ltd
Current assignee: Knorr Bremse Systeme fuer Schienenfahrzeuge GmbH; Knorr Bremse Systems for Commercial Vehicles Ltd
Priority date: 2007-04-23
Filing date: 2007-04-23
Publication date: 2008-10-29
Anticipated expiration: 2027-04-23
Also published as: GB0707817D0; GB2448691B; EP2148794A1; EP2148794B1; WO2008129306A1; HUE043714T2; ES2710376T3

Abstract

Control apparatus for a vehicle, in particular a trailer, comprises a braking ECU having discretely programmable storage means to carry operating data for one or more auxiliary functions of the vehicle and a lateral acceleration sensor adapted to detect lateral acceleration of the vehicle body. The output of the sensor is transmitted to the braking ECU which is adapted to determine a tilt angle alpha from the output of the lateral acceleration sensor. When the tilt angle exceeds a predetermined value, the braking ECU generates a signal indicating that the predetermined value has been exceeded. Preferably a warning is given to the operator. The trailer preferably has a raisable body 201 by a hydraulic actuator 202 to discharge its cargo at its rear 204. Stability of the trailer when discharging can be partially achieved by stabilizer legs 203.

Description

Tilt AnQIe Sensor and APParatus The invention relates to apparatus for

detecting tilt in a commercial vehicle, in particular but not exclusively, for detecting tilt in a tipper.

Heavy commercial tractor/trailer vehicles having a body that raises to discharge cargo camed on the trailer are well known and commonly known as tippers. With such a tipper, as the body raises the centre of gravity moves and therefore the possibility that the trailer becomes unstable increases and accordingly there is a risk that the trailer can fall over. This problem of the trailer falling over is more likely on trailers where the length of the container which holds the load is quite long, typically longer than 8m, where the movement of the centre of gravity is obviously greater.

Standards have been defined which give a rating to the trailer with respect to the maximum angle it can sustain before tipping becomes likely and these are at most 7 degrees and likely to be less. There have been a number of proposals for systems to provide a driver with a warning when there is the potential of trailer becoming unstable, or which interface with the tipping control to prevent the body from being lifted or continuing to be lifted beyond the maximum permitted angle. These are generally based on incilnometers and tend to be fitted by third party suppliers in the aftermarket These standalone systems have generally increased safety and reduced the likelihood of accidents but they are not part of the standard equipment of a trailer or commercial vehicle. Such systems therefore are not widely supported and suffer from increased installation and maintenance costs and are therefore frequently not specified by trailer builders or operators.

The present invention seeks to provide apparatus for detecting tilt in a commercial vehicle, in particular which can be integrated into original equipment According to the invention there is provided control apparatus for a vehicle, which apparatus comprises a braking ECU having discretely programmable storage means to cany operating data for one or more auxiliary functions of the vehicle, a lateral acceleration sensor adapted to detect lateral acceleration of the trailer body when the vehicle is moving below a predefined speed, which acceleration values are transmitted to the braking ECU and, wherein the braking ECU is adapted to determine a tilt angle of the trailer from the output of the lateral acceleration sensor such that when the tilt angle exceeds a predetermined value, the braking ECU generates a signal indicating that the predetermined value has been exceeded.

Preferably there is provided a warning system for the operator. Preferably there is a lifting control means.

An exemplary embodiment of the invention will now be descnbed in greater detail with reference to the drawings, in which: Fig. 1 shows a schematic of a trailer with its body raised Fig. 2 shows a schematic of ECU for a commercial vehide brake system Figure 1 shows a schematic of a trailer that is provided with a raisable body 201 in the raised position, so that the trailer's cargo can be discharged 204. Such trailers are commonly used for transporting building materials such as sand or aggregates and for taking waste from building sites. Tipping trucks are also common. The raisable body is raised by means of a hydraulically driven strut, which will typically be powered from a hydraulic pump powered from the tractor's drive train. In use, the trailer is parked and the brakes applied with the forward legs lowered 203 to provide stability.

The trailer is provided with a lateral acceleration sensor described in more detail with reference to Figure 2, which is adapted to detect and measure any lateral acceleration on the trailer body. During the End of Line Test at the end of manufacturing, the trailer will be on a level plane with the raisable body unraised and the lateral acceleration sensor may be calibrated for off-set. Calibration may also continue during driving.

In the event that lateral acceleration is detected, the value of the lateral acceleration detected is transmitted to the trailer brake control module. When the trailer is stationary, which can be detected from either the park brake status or from the wheel speed sensors 1, any lateral acceleration will result from the trailer is tilting due to the raising of the body and/or shifting of the load, as the continuing calibration will account for the trailer being parked on a slope or uneven ground. The values of the lateral acceleration in this case can be used to calibrate for the tilt angle of the trailer and so the values can determine the actual lateral tilt of the trailer. Via the diagnostic program the trailer manufacturer can program the ECU, as descnbed below, with the maximum tilt angle that is required for the raisable body to remain safe. Using the data from the tilt angle sensor, the brake control ECU can then determine if the tilt angle determined is below or above a pre-determined maximum tilt angle. The tilt angle is defined as the angle between the body of the trailer and a level plane, a.

Once the maximum tilt angle has been exceeded an output signal will be generated by the ECU controlling the brake. The signal will continue while the tilt angle remains above the maximum tilt angle.

It may be the case that the raisable body is near to the maximum tilt angle, and the body is moving. In this instance, the tilt angle sensor may generate an output that results in the output signal being turned von" and then off" several times in close succession, which is undesirable. This may be prevented by applying a hysteresis between the tilt angle sensor and the signal generator. This would also prevent "on/off" signals caused by small movements of the trailer platform.

Figure 2 shows a schematic of an electronic control unit (ECU) for a commercial vehicle brake system. The ECU receives inputs from a variety of sensors, which include wheel sensors 1, pressure sensors in the brake system, a lateral acceleration sensor and other auxiliary sensors 2. The permitted values for these detected sensor outputs are stored in a table, which the control software for the RSP IRoll Stability Program) calls to ensure that the system is working correctly.

The ECU comprises an EEPROM as a non-volatile storage memory means in which the memory is divided into two blocks. The first block comprises the main safety cntical control parameters in particular those related to the actuation and operation of the vehicle brakes. The second block of memory comprises a discretely programmable storage means for carrying operating data relating to one or more auxiliary functions.

When a vehicle has a dynamic vehicle control system installed such as RSP, an integral part of the trailer braking system is a lateral acceleration sensor which is primarily used to provide lateral acceleration information so that dynamic roll-overs when the vehicle is in motion can be prevented automatically by applying the trailer brakes, or the tractor brakes, or both the tractor and trailer brakes.

The lateral acceleration sensor can be adapted to detect lateral acceleration when the vehicle is stationary or moving slowly. The maximum speed will be defined as an auxiliary parameter when programming the ECU. When the vehicle is stationary or moving slowly and the vehide body is changing position the lateral acceleration detected will be related to the increase in tilt angle. When an auxiliary output of the ECU for the braking system is configured to uTilt Angle" the user can program the second block of the EEPROM with the vehicle and load parameters to define a safe tilt angle and maximum vehicle speed. When an unstable arrangement is reached the ECU may give a warning signal or directly interface with the dnve mechanism to prevent further increase of the tilt angle.

Claims

Claims 1. Control apparatus for a vehicle comprising a braking ECU

having discretely programmable storage means to carry operating data for one or more auxiliary functions of the vehicle, a lateral acceleration sensor adapted to detect lateral acceleration of the trailer body, which acceleration values are transmitted to the braking ECU, wherein the braking ECU is adapted to determine a tilt angle from the output of the lateral acceleration sensor such that when the tilt angle exceeds a predetermined value, the braking ECU generates a signal indicating that the predetermined value has been exceeded.
2. Control apparatus according to claim I wherein there is provided a warning system for the operator.
3. Control apparatus according to claims I or 2 wherein there is provided a lifting control means.
4. Control apparatus according to any one of claims I to 3 wherein a hysteresis between the tilt angle sensor and the braking ECU is provided so as to prevent rapid switching of the signal.
5. Control apparatus substantially as descnbed herein with reference to and illustrated in the accompanying drawings.